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Revision 1.4 by elmex, Sun Apr 27 20:20:20 2008 UTC vs.
Revision 1.97 by root, Thu Oct 2 11:07:59 2008 UTC

1	package AnyEvent::Handle;	1	package AnyEvent::Handle;
2		2
3	use warnings;	3	no warnings;
4	use strict;	4	use strict qw(subs vars);
5		5
6	use AnyEvent;	6	use AnyEvent ();
7	use IO::Handle;	7	use AnyEvent::Util qw(WSAEWOULDBLOCK);
		8	use Scalar::Util ();
		9	use Carp ();
		10	use Fcntl ();
8	use Errno qw/EAGAIN EINTR/;	11	use Errno qw(EAGAIN EINTR);
9		12
10	=head1 NAME	13	=head1 NAME
11		14
12	AnyEvent::Handle - non-blocking I/O on filehandles via AnyEvent	15	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
13		16
14	=head1 VERSION
15
16	Version 0.01
17
18	=cut	17	=cut
19		18
20	our $VERSION = '0.01';	19	our $VERSION = 4.3;
21		20
22	=head1 SYNOPSIS	21	=head1 SYNOPSIS
23		22
24	use AnyEvent;	23	use AnyEvent;
25	use AnyEvent::Handle;	24	use AnyEvent::Handle;
26		25
27	my $cv = AnyEvent->condvar;	26	my $cv = AnyEvent->condvar;
28		27
29	my $ae_fh = AnyEvent::Handle->new (fh => \*STDIN);	28	my $handle =
30
31	$ae_fh->on_eof (sub { $cv->broadcast });
32
33	$ae_fh->readlines (sub {
34	my ($ae_fh, @lines) = @_;
35	for (@lines) {
36	chomp;
37	print "Line: $_";
38	}
39	});
40
41	# or use the constructor to pass the callback:
42
43	my $ae_fh2 =
44	AnyEvent::Handle->new (	29	AnyEvent::Handle->new (
45	fh => \*STDIN,	30	fh => \*STDIN,
46	on_eof => sub {	31	on_eof => sub {
47	$cv->broadcast;	32	$cv->broadcast;
48	},	33	},
		34	);
		35
		36	# send some request line
		37	$handle->push_write ("getinfo\015\012");
		38
		39	# read the response line
		40	$handle->push_read (line => sub {
		41	my ($handle, $line) = @_;
		42	warn "read line <$line>\n";
		43	$cv->send;
		44	});
		45
		46	$cv->recv;
		47
		48	=head1 DESCRIPTION
		49
		50	This module is a helper module to make it easier to do event-based I/O on
		51	filehandles. For utility functions for doing non-blocking connects and accepts
		52	on sockets see L<AnyEvent::Util>.
		53
		54	The L<AnyEvent::Intro> tutorial contains some well-documented
		55	AnyEvent::Handle examples.
		56
		57	In the following, when the documentation refers to of "bytes" then this
		58	means characters. As sysread and syswrite are used for all I/O, their
		59	treatment of characters applies to this module as well.
		60
		61	All callbacks will be invoked with the handle object as their first
		62	argument.
		63
		64	=head2 SIGPIPE is not handled by this module
		65
		66	SIGPIPE is not handled by this module, so one of the practical
		67	requirements of using it is to ignore SIGPIPE (C<$SIG{PIPE} =
		68	'IGNORE'>). At least, this is highly recommend in a networked program: If
		69	you use AnyEvent::Handle in a filter program (like sort), exiting on
		70	SIGPIPE is probably the right thing to do.
		71
		72	=head1 METHODS
		73
		74	=over 4
		75
		76	=item B<new (%args)>
		77
		78	The constructor supports these arguments (all as key => value pairs).
		79
		80	=over 4
		81
		82	=item fh => $filehandle [MANDATORY]
		83
		84	The filehandle this L<AnyEvent::Handle> object will operate on.
		85
		86	NOTE: The filehandle will be set to non-blocking mode (using
		87	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		88	that mode.
		89
		90	=item on_eof => $cb->($handle)
		91
		92	Set the callback to be called when an end-of-file condition is detected,
		93	i.e. in the case of a socket, when the other side has closed the
		94	connection cleanly.
		95
		96	For sockets, this just means that the other side has stopped sending data,
		97	you can still try to write data, and, in fact, one can return from the eof
		98	callback and continue writing data, as only the read part has been shut
		99	down.
		100
		101	While not mandatory, it is I<highly> recommended to set an eof callback,
		102	otherwise you might end up with a closed socket while you are still
		103	waiting for data.
		104
		105	If an EOF condition has been detected but no C<on_eof> callback has been
		106	set, then a fatal error will be raised with C<$!> set to <0>.
		107
		108	=item on_error => $cb->($handle, $fatal)
		109
		110	This is the error callback, which is called when, well, some error
		111	occured, such as not being able to resolve the hostname, failure to
		112	connect or a read error.
		113
		114	Some errors are fatal (which is indicated by C<$fatal> being true). On
		115	fatal errors the handle object will be shut down and will not be usable
		116	(but you are free to look at the current C<< ->rbuf >>). Examples of fatal
		117	errors are an EOF condition with active (but unsatisifable) read watchers
		118	(C<EPIPE>) or I/O errors.
		119
		120	Non-fatal errors can be retried by simply returning, but it is recommended
		121	to simply ignore this parameter and instead abondon the handle object
		122	when this callback is invoked. Examples of non-fatal errors are timeouts
		123	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		124
		125	On callback entrance, the value of C<$!> contains the operating system
		126	error (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT> or C<EBADMSG>).
		127
		128	While not mandatory, it is I<highly> recommended to set this callback, as
		129	you will not be notified of errors otherwise. The default simply calls
		130	C<croak>.
		131
		132	=item on_read => $cb->($handle)
		133
		134	This sets the default read callback, which is called when data arrives
		135	and no read request is in the queue (unlike read queue callbacks, this
		136	callback will only be called when at least one octet of data is in the
		137	read buffer).
		138
		139	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
		140	method or access the C<$handle->{rbuf}> member directly.
		141
		142	When an EOF condition is detected then AnyEvent::Handle will first try to
		143	feed all the remaining data to the queued callbacks and C<on_read> before
		144	calling the C<on_eof> callback. If no progress can be made, then a fatal
		145	error will be raised (with C<$!> set to C<EPIPE>).
		146
		147	=item on_drain => $cb->($handle)
		148
		149	This sets the callback that is called when the write buffer becomes empty
		150	(or when the callback is set and the buffer is empty already).
		151
		152	To append to the write buffer, use the C<< ->push_write >> method.
		153
		154	This callback is useful when you don't want to put all of your write data
		155	into the queue at once, for example, when you want to write the contents
		156	of some file to the socket you might not want to read the whole file into
		157	memory and push it into the queue, but instead only read more data from
		158	the file when the write queue becomes empty.
		159
		160	=item timeout => $fractional_seconds
		161
		162	If non-zero, then this enables an "inactivity" timeout: whenever this many
		163	seconds pass without a successful read or write on the underlying file
		164	handle, the C<on_timeout> callback will be invoked (and if that one is
		165	missing, a non-fatal C<ETIMEDOUT> error will be raised).
		166
		167	Note that timeout processing is also active when you currently do not have
		168	any outstanding read or write requests: If you plan to keep the connection
		169	idle then you should disable the timout temporarily or ignore the timeout
		170	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		171	restart the timeout.
		172
		173	Zero (the default) disables this timeout.
		174
		175	=item on_timeout => $cb->($handle)
		176
		177	Called whenever the inactivity timeout passes. If you return from this
		178	callback, then the timeout will be reset as if some activity had happened,
		179	so this condition is not fatal in any way.
		180
		181	=item rbuf_max => <bytes>
		182
		183	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		184	when the read buffer ever (strictly) exceeds this size. This is useful to
		185	avoid some forms of denial-of-service attacks.
		186
		187	For example, a server accepting connections from untrusted sources should
		188	be configured to accept only so-and-so much data that it cannot act on
		189	(for example, when expecting a line, an attacker could send an unlimited
		190	amount of data without a callback ever being called as long as the line
		191	isn't finished).
		192
		193	=item autocork => <boolean>
		194
		195	When disabled (the default), then C<push_write> will try to immediately
		196	write the data to the handle, if possible. This avoids having to register
		197	a write watcher and wait for the next event loop iteration, but can
		198	be inefficient if you write multiple small chunks (on the wire, this
		199	disadvantage is usually avoided by your kernel's nagle algorithm, see
		200	C<no_delay>, but this option can save costly syscalls).
		201
		202	When enabled, then writes will always be queued till the next event loop
		203	iteration. This is efficient when you do many small writes per iteration,
		204	but less efficient when you do a single write only per iteration (or when
		205	the write buffer often is full). It also increases write latency.
		206
		207	=item no_delay => <boolean>
		208
		209	When doing small writes on sockets, your operating system kernel might
		210	wait a bit for more data before actually sending it out. This is called
		211	the Nagle algorithm, and usually it is beneficial.
		212
		213	In some situations you want as low a delay as possible, which can be
		214	accomplishd by setting this option to a true value.
		215
		216	The default is your opertaing system's default behaviour (most likely
		217	enabled), this option explicitly enables or disables it, if possible.
		218
		219	=item read_size => <bytes>
		220
		221	The default read block size (the amount of bytes this module will
		222	try to read during each loop iteration, which affects memory
		223	requirements). Default: C<8192>.
		224
		225	=item low_water_mark => <bytes>
		226
		227	Sets the amount of bytes (default: C<0>) that make up an "empty" write
		228	buffer: If the write reaches this size or gets even samller it is
		229	considered empty.
		230
		231	Sometimes it can be beneficial (for performance reasons) to add data to
		232	the write buffer before it is fully drained, but this is a rare case, as
		233	the operating system kernel usually buffers data as well, so the default
		234	is good in almost all cases.
		235
		236	=item linger => <seconds>
		237
		238	If non-zero (default: C<3600>), then the destructor of the
		239	AnyEvent::Handle object will check whether there is still outstanding
		240	write data and will install a watcher that will write this data to the
		241	socket. No errors will be reported (this mostly matches how the operating
		242	system treats outstanding data at socket close time).
		243
		244	This will not work for partial TLS data that could not be encoded
		245	yet. This data will be lost. Calling the C<stoptls> method in time might
		246	help.
		247
		248	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
		249
		250	When this parameter is given, it enables TLS (SSL) mode, that means
		251	AnyEvent will start a TLS handshake as soon as the conenction has been
		252	established and will transparently encrypt/decrypt data afterwards.
		253
		254	TLS mode requires Net::SSLeay to be installed (it will be loaded
		255	automatically when you try to create a TLS handle): this module doesn't
		256	have a dependency on that module, so if your module requires it, you have
		257	to add the dependency yourself.
		258
		259	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		260	C<accept>, and for the TLS client side of a connection, use C<connect>
		261	mode.
		262
		263	You can also provide your own TLS connection object, but you have
		264	to make sure that you call either C<Net::SSLeay::set_connect_state>
		265	or C<Net::SSLeay::set_accept_state> on it before you pass it to
		266	AnyEvent::Handle.
		267
		268	See the C<< ->starttls >> method for when need to start TLS negotiation later.
		269
		270	=item tls_ctx => $ssl_ctx
		271
		272	Use the given C<Net::SSLeay::CTX> object to create the new TLS connection
		273	(unless a connection object was specified directly). If this parameter is
		274	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
		275
		276	=item json => JSON or JSON::XS object
		277
		278	This is the json coder object used by the C<json> read and write types.
		279
		280	If you don't supply it, then AnyEvent::Handle will create and use a
		281	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		282	texts.
		283
		284	Note that you are responsible to depend on the JSON module if you want to
		285	use this functionality, as AnyEvent does not have a dependency itself.
		286
		287	=back
		288
		289	=cut
		290
		291	sub new {
		292	my $class = shift;
		293
		294	my $self = bless { @_ }, $class;
		295
		296	$self->{fh} or Carp::croak "mandatory argument fh is missing";
		297
		298	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
		299
		300	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		301	if $self->{tls};
		302
		303	$self->{_activity} = AnyEvent->now;
		304	$self->_timeout;
		305
		306	$self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
		307	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
		308
		309	$self->start_read
		310	if $self->{on_read};
		311
		312	$self
		313	}
		314
		315	sub _shutdown {
		316	my ($self) = @_;
		317
		318	delete $self->{_tw};
		319	delete $self->{_rw};
		320	delete $self->{_ww};
		321	delete $self->{fh};
		322
		323	&_freetls;
		324
		325	delete $self->{on_read};
		326	delete $self->{_queue};
		327	}
		328
		329	sub _error {
		330	my ($self, $errno, $fatal) = @_;
		331
		332	$self->_shutdown
		333	if $fatal;
		334
		335	$! = $errno;
		336
		337	if ($self->{on_error}) {
		338	$self->{on_error}($self, $fatal);
		339	} else {
		340	Carp::croak "AnyEvent::Handle uncaught error: $!";
		341	}
		342	}
		343
		344	=item $fh = $handle->fh
		345
		346	This method returns the file handle used to create the L<AnyEvent::Handle> object.
		347
		348	=cut
		349
		350	sub fh { $_[0]{fh} }
		351
		352	=item $handle->on_error ($cb)
		353
		354	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
		355
		356	=cut
		357
		358	sub on_error {
		359	$_[0]{on_error} = $_[1];
		360	}
		361
		362	=item $handle->on_eof ($cb)
		363
		364	Replace the current C<on_eof> callback (see the C<on_eof> constructor argument).
		365
		366	=cut
		367
		368	sub on_eof {
		369	$_[0]{on_eof} = $_[1];
		370	}
		371
		372	=item $handle->on_timeout ($cb)
		373
		374	Replace the current C<on_timeout> callback, or disables the callback (but
		375	not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
		376	argument and method.
		377
		378	=cut
		379
		380	sub on_timeout {
		381	$_[0]{on_timeout} = $_[1];
		382	}
		383
		384	=item $handle->autocork ($boolean)
		385
		386	Enables or disables the current autocork behaviour (see C<autocork>
		387	constructor argument).
		388
		389	=cut
		390
		391	=item $handle->no_delay ($boolean)
		392
		393	Enables or disables the C<no_delay> setting (see constructor argument of
		394	the same name for details).
		395
		396	=cut
		397
		398	sub no_delay {
		399	$_[0]{no_delay} = $_[1];
		400
		401	eval {
		402	local $SIG{__DIE__};
		403	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];
		404	};
		405	}
		406
		407	#############################################################################
		408
		409	=item $handle->timeout ($seconds)
		410
		411	Configures (or disables) the inactivity timeout.
		412
		413	=cut
		414
		415	sub timeout {
		416	my ($self, $timeout) = @_;
		417
		418	$self->{timeout} = $timeout;
		419	$self->_timeout;
		420	}
		421
		422	# reset the timeout watcher, as neccessary
		423	# also check for time-outs
		424	sub _timeout {
		425	my ($self) = @_;
		426
		427	if ($self->{timeout}) {
		428	my $NOW = AnyEvent->now;
		429
		430	# when would the timeout trigger?
		431	my $after = $self->{_activity} + $self->{timeout} - $NOW;
		432
		433	# now or in the past already?
		434	if ($after <= 0) {
		435	$self->{_activity} = $NOW;
		436
		437	if ($self->{on_timeout}) {
		438	$self->{on_timeout}($self);
		439	} else {
		440	$self->_error (&Errno::ETIMEDOUT);
		441	}
		442
		443	# callback could have changed timeout value, optimise
		444	return unless $self->{timeout};
		445
		446	# calculate new after
		447	$after = $self->{timeout};
		448	}
		449
		450	Scalar::Util::weaken $self;
		451	return unless $self; # ->error could have destroyed $self
		452
		453	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
		454	delete $self->{_tw};
		455	$self->_timeout;
		456	});
		457	} else {
		458	delete $self->{_tw};
		459	}
		460	}
		461
		462	#############################################################################
		463
		464	=back
		465
		466	=head2 WRITE QUEUE
		467
		468	AnyEvent::Handle manages two queues per handle, one for writing and one
		469	for reading.
		470
		471	The write queue is very simple: you can add data to its end, and
		472	AnyEvent::Handle will automatically try to get rid of it for you.
		473
		474	When data could be written and the write buffer is shorter then the low
		475	water mark, the C<on_drain> callback will be invoked.
		476
		477	=over 4
		478
		479	=item $handle->on_drain ($cb)
		480
		481	Sets the C<on_drain> callback or clears it (see the description of
		482	C<on_drain> in the constructor).
		483
		484	=cut
		485
		486	sub on_drain {
		487	my ($self, $cb) = @_;
		488
		489	$self->{on_drain} = $cb;
		490
		491	$cb->($self)
		492	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
		493	}
		494
		495	=item $handle->push_write ($data)
		496
		497	Queues the given scalar to be written. You can push as much data as you
		498	want (only limited by the available memory), as C<AnyEvent::Handle>
		499	buffers it independently of the kernel.
		500
		501	=cut
		502
		503	sub _drain_wbuf {
		504	my ($self) = @_;
		505
		506	if (!$self->{_ww} && length $self->{wbuf}) {
		507
		508	Scalar::Util::weaken $self;
		509
		510	my $cb = sub {
		511	my $len = syswrite $self->{fh}, $self->{wbuf};
		512
		513	if ($len >= 0) {
		514	substr $self->{wbuf}, 0, $len, "";
		515
		516	$self->{_activity} = AnyEvent->now;
		517
		518	$self->{on_drain}($self)
		519	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
		520	&& $self->{on_drain};
		521
		522	delete $self->{_ww} unless length $self->{wbuf};
		523	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		524	$self->_error ($!, 1);
		525	}
		526	};
		527
		528	# try to write data immediately
		529	$cb->() unless $self->{autocork};
		530
		531	# if still data left in wbuf, we need to poll
		532	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
		533	if length $self->{wbuf};
		534	};
		535	}
		536
		537	our %WH;
		538
		539	sub register_write_type($$) {
		540	$WH{$_[0]} = $_[1];
		541	}
		542
		543	sub push_write {
		544	my $self = shift;
		545
		546	if (@_ > 1) {
		547	my $type = shift;
		548
		549	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
		550	->($self, @_);
		551	}
		552
		553	if ($self->{tls}) {
		554	$self->{_tls_wbuf} .= $_[0];
		555
		556	&_dotls ($self);
		557	} else {
		558	$self->{wbuf} .= $_[0];
		559	$self->_drain_wbuf;
		560	}
		561	}
		562
		563	=item $handle->push_write (type => @args)
		564
		565	Instead of formatting your data yourself, you can also let this module do
		566	the job by specifying a type and type-specific arguments.
		567
		568	Predefined types are (if you have ideas for additional types, feel free to
		569	drop by and tell us):
		570
		571	=over 4
		572
		573	=item netstring => $string
		574
		575	Formats the given value as netstring
		576	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		577
		578	=cut
		579
		580	register_write_type netstring => sub {
		581	my ($self, $string) = @_;
		582
		583	(length $string) . ":$string,"
		584	};
		585
		586	=item packstring => $format, $data
		587
		588	An octet string prefixed with an encoded length. The encoding C<$format>
		589	uses the same format as a Perl C<pack> format, but must specify a single
		590	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		591	optional C<!>, C<< < >> or C<< > >> modifier).
		592
		593	=cut
		594
		595	register_write_type packstring => sub {
		596	my ($self, $format, $string) = @_;
		597
		598	pack "$format/a*", $string
		599	};
		600
		601	=item json => $array_or_hashref
		602
		603	Encodes the given hash or array reference into a JSON object. Unless you
		604	provide your own JSON object, this means it will be encoded to JSON text
		605	in UTF-8.
		606
		607	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		608	one end of a handle and read them at the other end without using any
		609	additional framing.
		610
		611	The generated JSON text is guaranteed not to contain any newlines: While
		612	this module doesn't need delimiters after or between JSON texts to be
		613	able to read them, many other languages depend on that.
		614
		615	A simple RPC protocol that interoperates easily with others is to send
		616	JSON arrays (or objects, although arrays are usually the better choice as
		617	they mimic how function argument passing works) and a newline after each
		618	JSON text:
		619
		620	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		621	$handle->push_write ("\012");
		622
		623	An AnyEvent::Handle receiver would simply use the C<json> read type and
		624	rely on the fact that the newline will be skipped as leading whitespace:
		625
		626	$handle->push_read (json => sub { my $array = $_[1]; ... });
		627
		628	Other languages could read single lines terminated by a newline and pass
		629	this line into their JSON decoder of choice.
		630
		631	=cut
		632
		633	register_write_type json => sub {
		634	my ($self, $ref) = @_;
		635
		636	require JSON;
		637
		638	$self->{json} ? $self->{json}->encode ($ref)
		639	: JSON::encode_json ($ref)
		640	};
		641
		642	=item storable => $reference
		643
		644	Freezes the given reference using L<Storable> and writes it to the
		645	handle. Uses the C<nfreeze> format.
		646
		647	=cut
		648
		649	register_write_type storable => sub {
		650	my ($self, $ref) = @_;
		651
		652	require Storable;
		653
		654	pack "w/a*", Storable::nfreeze ($ref)
		655	};
		656
		657	=back
		658
		659	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
		660
		661	This function (not method) lets you add your own types to C<push_write>.
		662	Whenever the given C<type> is used, C<push_write> will invoke the code
		663	reference with the handle object and the remaining arguments.
		664
		665	The code reference is supposed to return a single octet string that will
		666	be appended to the write buffer.
		667
		668	Note that this is a function, and all types registered this way will be
		669	global, so try to use unique names.
		670
		671	=cut
		672
		673	#############################################################################
		674
		675	=back
		676
		677	=head2 READ QUEUE
		678
		679	AnyEvent::Handle manages two queues per handle, one for writing and one
		680	for reading.
		681
		682	The read queue is more complex than the write queue. It can be used in two
		683	ways, the "simple" way, using only C<on_read> and the "complex" way, using
		684	a queue.
		685
		686	In the simple case, you just install an C<on_read> callback and whenever
		687	new data arrives, it will be called. You can then remove some data (if
		688	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
		689	leave the data there if you want to accumulate more (e.g. when only a
		690	partial message has been received so far).
		691
		692	In the more complex case, you want to queue multiple callbacks. In this
		693	case, AnyEvent::Handle will call the first queued callback each time new
		694	data arrives (also the first time it is queued) and removes it when it has
		695	done its job (see C<push_read>, below).
		696
		697	This way you can, for example, push three line-reads, followed by reading
		698	a chunk of data, and AnyEvent::Handle will execute them in order.
		699
		700	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
		701	the specified number of bytes which give an XML datagram.
		702
		703	# in the default state, expect some header bytes
		704	$handle->on_read (sub {
		705	# some data is here, now queue the length-header-read (4 octets)
		706	shift->unshift_read (chunk => 4, sub {
		707	# header arrived, decode
		708	my $len = unpack "N", $_[1];
		709
		710	# now read the payload
		711	shift->unshift_read (chunk => $len, sub {
		712	my $xml = $_[1];
		713	# handle xml
		714	});
		715	});
		716	});
		717
		718	Example 2: Implement a client for a protocol that replies either with "OK"
		719	and another line or "ERROR" for the first request that is sent, and 64
		720	bytes for the second request. Due to the availability of a queue, we can
		721	just pipeline sending both requests and manipulate the queue as necessary
		722	in the callbacks.
		723
		724	When the first callback is called and sees an "OK" response, it will
		725	C<unshift> another line-read. This line-read will be queued I<before> the
		726	64-byte chunk callback.
		727
		728	# request one, returns either "OK + extra line" or "ERROR"
		729	$handle->push_write ("request 1\015\012");
		730
		731	# we expect "ERROR" or "OK" as response, so push a line read
		732	$handle->push_read (line => sub {
		733	# if we got an "OK", we have to _prepend_ another line,
		734	# so it will be read before the second request reads its 64 bytes
		735	# which are already in the queue when this callback is called
		736	# we don't do this in case we got an error
		737	if ($_[1] eq "OK") {
49	on_readline => sub {	738	$_[0]->unshift_read (line => sub {
50	my ($ae_fh, @lines) = @_;	739	my $response = $_[1];
51	for (@lines) {	740	...
52	chomp;	741	});
53	print "Line: $_";	742	}
		743	});
		744
		745	# request two, simply returns 64 octets
		746	$handle->push_write ("request 2\015\012");
		747
		748	# simply read 64 bytes, always
		749	$handle->push_read (chunk => 64, sub {
		750	my $response = $_[1];
		751	...
		752	});
		753
		754	=over 4
		755
		756	=cut
		757
		758	sub _drain_rbuf {
		759	my ($self) = @_;
		760
		761	local $self->{_in_drain} = 1;
		762
		763	if (
		764	defined $self->{rbuf_max}
		765	&& $self->{rbuf_max} < length $self->{rbuf}
		766	) {
		767	$self->_error (&Errno::ENOSPC, 1), return;
		768	}
		769
		770	while () {
		771	my $len = length $self->{rbuf};
		772
		773	if (my $cb = shift @{ $self->{_queue} }) {
		774	unless ($cb->($self)) {
		775	if ($self->{_eof}) {
		776	# no progress can be made (not enough data and no data forthcoming)
		777	$self->_error (&Errno::EPIPE, 1), return;
54	}	778	}
		779
		780	unshift @{ $self->{_queue} }, $cb;
		781	last;
55	}	782	}
56	);
57
58	$cv->wait;
59
60	=head1 DESCRIPTION
61
62	This module is a helper module to make it easier to do non-blocking I/O
63	on filehandles (and sockets, see L<AnyEvent::Socket>).
64
65	The event loop is provided by L<AnyEvent>.
66
67	=head1 METHODS
68
69	=over 4
70
71	=item B<new (%args)>
72
73	The constructor has these arguments:
74
75	=over 4
76
77	=item fh => $filehandle
78
79	The filehandle this L<AnyEvent::Handle> object will operate on.
80
81	NOTE: The filehandle will be set to non-blocking.
82
83	=item read_block_size => $size
84
85	The default read block size use for reads via the C<on_read>
86	method.
87
88	=item on_read => $cb
89
90	=item on_eof => $cb
91
92	=item on_error => $cb
93
94	These are shortcuts, that will call the corresponding method and set the callback to C<$cb>.
95
96	=item on_readline => $cb
97
98	The C<readlines> method is called with the default seperator and C<$cb> as callback
99	for you.
100
101	=back
102
103	=cut
104
105	sub new {
106	my $this = shift;
107	my $class = ref($this) || $this;
108	my $self = {
109	read_block_size => 4096,
110	rbuf => '',
111	@_
112	};
113	bless $self, $class;
114
115	$self->{fh}->blocking (0) if $self->{fh};
116
117	if ($self->{on_read}) {
118	$self->on_read ($self->{on_read});
119
120	} elsif ($self->{on_readline}) {	783	} elsif ($self->{on_read}) {
121	$self->readlines ($self->{on_readline});	784	last unless $len;
122		785
		786	$self->{on_read}($self);
		787
		788	if (
		789	$len == length $self->{rbuf} # if no data has been consumed
		790	&& !@{ $self->{_queue} } # and the queue is still empty
		791	&& $self->{on_read} # but we still have on_read
		792	) {
		793	# no further data will arrive
		794	# so no progress can be made
		795	$self->_error (&Errno::EPIPE, 1), return
		796	if $self->{_eof};
		797
		798	last; # more data might arrive
		799	}
		800	} else {
		801	# read side becomes idle
		802	delete $self->{_rw} unless $self->{tls};
		803	last;
		804	}
		805	}
		806
123	} elsif ($self->{on_eof}) {	807	if ($self->{_eof}) {
124	$self->on_eof ($self->{on_eof});
125
126	} elsif ($self->{on_error}) {	808	if ($self->{on_eof}) {
127	$self->on_eof ($self->{on_error});	809	$self->{on_eof}($self)
		810	} else {
		811	$self->_error (0, 1);
		812	}
128	}	813	}
129		814
130	return $self	815	# may need to restart read watcher
		816	unless ($self->{_rw}) {
		817	$self->start_read
		818	if $self->{on_read} || @{ $self->{_queue} };
		819	}
131	}	820	}
132		821
133	=item B<fh>	822	=item $handle->on_read ($cb)
134		823
135	This method returns the filehandle of the L<AnyEvent::Handle> object.	824	This replaces the currently set C<on_read> callback, or clears it (when
136		825	the new callback is C<undef>). See the description of C<on_read> in the
137	=cut	826	constructor.
138
139	sub fh { $_[0]->{fh} }
140
141	=item B<on_read ($callback)>
142
143	This method installs a C<$callback> that will be called
144	when new data arrived. You can access the read buffer via the C<rbuf>
145	method (see below).
146
147	The first argument of the C<$callback> will be the L<AnyEvent::Handle> object.
148		827
149	=cut	828	=cut
150		829
151	sub on_read {	830	sub on_read {
152	my ($self, $cb) = @_;	831	my ($self, $cb) = @_;
		832
153	$self->{on_read} = $cb;	833	$self->{on_read} = $cb;
		834	$self->_drain_rbuf if $cb && !$self->{_in_drain};
		835	}
154		836
155	unless (defined $self->{on_read}) {	837	=item $handle->rbuf
156	delete $self->{on_read_w};	838
		839	Returns the read buffer (as a modifiable lvalue).
		840
		841	You can access the read buffer directly as the C<< ->{rbuf} >> member, if
		842	you want.
		843
		844	NOTE: The read buffer should only be used or modified if the C<on_read>,
		845	C<push_read> or C<unshift_read> methods are used. The other read methods
		846	automatically manage the read buffer.
		847
		848	=cut
		849
		850	sub rbuf : lvalue {
		851	$_[0]{rbuf}
		852	}
		853
		854	=item $handle->push_read ($cb)
		855
		856	=item $handle->unshift_read ($cb)
		857
		858	Append the given callback to the end of the queue (C<push_read>) or
		859	prepend it (C<unshift_read>).
		860
		861	The callback is called each time some additional read data arrives.
		862
		863	It must check whether enough data is in the read buffer already.
		864
		865	If not enough data is available, it must return the empty list or a false
		866	value, in which case it will be called repeatedly until enough data is
		867	available (or an error condition is detected).
		868
		869	If enough data was available, then the callback must remove all data it is
		870	interested in (which can be none at all) and return a true value. After returning
		871	true, it will be removed from the queue.
		872
		873	=cut
		874
		875	our %RH;
		876
		877	sub register_read_type($$) {
		878	$RH{$_[0]} = $_[1];
		879	}
		880
		881	sub push_read {
		882	my $self = shift;
		883	my $cb = pop;
		884
		885	if (@_) {
		886	my $type = shift;
		887
		888	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
		889	->($self, $cb, @_);
		890	}
		891
		892	push @{ $self->{_queue} }, $cb;
		893	$self->_drain_rbuf unless $self->{_in_drain};
		894	}
		895
		896	sub unshift_read {
		897	my $self = shift;
		898	my $cb = pop;
		899
		900	if (@_) {
		901	my $type = shift;
		902
		903	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
		904	->($self, $cb, @_);
		905	}
		906
		907
		908	unshift @{ $self->{_queue} }, $cb;
		909	$self->_drain_rbuf unless $self->{_in_drain};
		910	}
		911
		912	=item $handle->push_read (type => @args, $cb)
		913
		914	=item $handle->unshift_read (type => @args, $cb)
		915
		916	Instead of providing a callback that parses the data itself you can chose
		917	between a number of predefined parsing formats, for chunks of data, lines
		918	etc.
		919
		920	Predefined types are (if you have ideas for additional types, feel free to
		921	drop by and tell us):
		922
		923	=over 4
		924
		925	=item chunk => $octets, $cb->($handle, $data)
		926
		927	Invoke the callback only once C<$octets> bytes have been read. Pass the
		928	data read to the callback. The callback will never be called with less
		929	data.
		930
		931	Example: read 2 bytes.
		932
		933	$handle->push_read (chunk => 2, sub {
		934	warn "yay ", unpack "H*", $_[1];
		935	});
		936
		937	=cut
		938
		939	register_read_type chunk => sub {
		940	my ($self, $cb, $len) = @_;
		941
		942	sub {
		943	$len <= length $_[0]{rbuf} or return;
		944	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
		945	1
		946	}
		947	};
		948
		949	=item line => [$eol, ]$cb->($handle, $line, $eol)
		950
		951	The callback will be called only once a full line (including the end of
		952	line marker, C<$eol>) has been read. This line (excluding the end of line
		953	marker) will be passed to the callback as second argument (C<$line>), and
		954	the end of line marker as the third argument (C<$eol>).
		955
		956	The end of line marker, C<$eol>, can be either a string, in which case it
		957	will be interpreted as a fixed record end marker, or it can be a regex
		958	object (e.g. created by C<qr>), in which case it is interpreted as a
		959	regular expression.
		960
		961	The end of line marker argument C<$eol> is optional, if it is missing (NOT
		962	undef), then C<qr|\015?\012|> is used (which is good for most internet
		963	protocols).
		964
		965	Partial lines at the end of the stream will never be returned, as they are
		966	not marked by the end of line marker.
		967
		968	=cut
		969
		970	register_read_type line => sub {
		971	my ($self, $cb, $eol) = @_;
		972
		973	if (@_ < 3) {
		974	# this is more than twice as fast as the generic code below
		975	sub {
		976	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		977
		978	$cb->($_[0], $1, $2);
		979	1
		980	}
		981	} else {
		982	$eol = quotemeta $eol unless ref $eol;
		983	$eol = qr|^(.*?)($eol)|s;
		984
		985	sub {
		986	$_[0]{rbuf} =~ s/$eol// or return;
		987
		988	$cb->($_[0], $1, $2);
		989	1
		990	}
		991	}
		992	};
		993
		994	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		995
		996	Makes a regex match against the regex object C<$accept> and returns
		997	everything up to and including the match.
		998
		999	Example: read a single line terminated by '\n'.
		1000
		1001	$handle->push_read (regex => qr<\n>, sub { ... });
		1002
		1003	If C<$reject> is given and not undef, then it determines when the data is
		1004	to be rejected: it is matched against the data when the C<$accept> regex
		1005	does not match and generates an C<EBADMSG> error when it matches. This is
		1006	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1007	receive buffer overflow).
		1008
		1009	Example: expect a single decimal number followed by whitespace, reject
		1010	anything else (not the use of an anchor).
		1011
		1012	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1013
		1014	If C<$skip> is given and not C<undef>, then it will be matched against
		1015	the receive buffer when neither C<$accept> nor C<$reject> match,
		1016	and everything preceding and including the match will be accepted
		1017	unconditionally. This is useful to skip large amounts of data that you
		1018	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1019	have to start matching from the beginning. This is purely an optimisation
		1020	and is usually worth only when you expect more than a few kilobytes.
		1021
		1022	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1023	expect the header to be very large (it isn't in practise, but...), we use
		1024	a skip regex to skip initial portions. The skip regex is tricky in that
		1025	it only accepts something not ending in either \015 or \012, as these are
		1026	required for the accept regex.
		1027
		1028	$handle->push_read (regex =>
		1029	qr<\015\012\015\012>,
		1030	undef, # no reject
		1031	qr<^.*[^\015\012]>,
		1032	sub { ... });
		1033
		1034	=cut
		1035
		1036	register_read_type regex => sub {
		1037	my ($self, $cb, $accept, $reject, $skip) = @_;
		1038
		1039	my $data;
		1040	my $rbuf = \$self->{rbuf};
		1041
		1042	sub {
		1043	# accept
		1044	if ($$rbuf =~ $accept) {
		1045	$data .= substr $$rbuf, 0, $+[0], "";
		1046	$cb->($self, $data);
157	return;	1047	return 1;
		1048	}
		1049
		1050	# reject
		1051	if ($reject && $$rbuf =~ $reject) {
		1052	$self->_error (&Errno::EBADMSG);
		1053	}
		1054
		1055	# skip
		1056	if ($skip && $$rbuf =~ $skip) {
		1057	$data .= substr $$rbuf, 0, $+[0], "";
		1058	}
		1059
		1060	()
158	}	1061	}
159		1062	};
160	$self->{on_read_w} =	1063
161	AnyEvent->io (poll => 'r', fh => $self->{fh}, cb => sub {	1064	=item netstring => $cb->($handle, $string)
162	#d# warn "READ:[$self->{read_size}] $self->{read_block_size} : ".length ($self->{rbuf})."\n";	1065
163	my $rbuf_len = length $self->{rbuf};	1066	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
164	my $l;	1067
165	if (defined $self->{read_size}) {	1068	Throws an error with C<$!> set to EBADMSG on format violations.
166	$l = sysread $self->{fh}, $self->{rbuf},	1069
167	($self->{read_size} - $rbuf_len), $rbuf_len;	1070	=cut
168	} else {	1071
169	$l = sysread $self->{fh}, $self->{rbuf}, $self->{read_block_size}, $rbuf_len;	1072	register_read_type netstring => sub {
		1073	my ($self, $cb) = @_;
		1074
		1075	sub {
		1076	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1077	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1078	$self->_error (&Errno::EBADMSG);
170	}	1079	}
171	#d# warn "READL $l [$self->{rbuf}]\n";	1080	return;
		1081	}
172		1082
173	if (not defined $l) {	1083	my $len = $1;
174	return if $! == EAGAIN || $! == EINTR;
175	$self->{on_error}->($self) if $self->{on_error};
176	delete $self->{on_read_w};
177		1084
178	} elsif ($l == 0) {	1085	$self->unshift_read (chunk => $len, sub {
179	$self->{on_eof}->($self) if $self->{on_eof};	1086	my $string = $_[1];
180	delete $self->{on_read_w};	1087	$_[0]->unshift_read (chunk => 1, sub {
181		1088	if ($_[1] eq ",") {
		1089	$cb->($_[0], $string);
182	} else {	1090	} else {
183	$self->{on_read}->($self);	1091	$self->_error (&Errno::EBADMSG);
		1092	}
		1093	});
		1094	});
		1095
		1096	1
		1097	}
		1098	};
		1099
		1100	=item packstring => $format, $cb->($handle, $string)
		1101
		1102	An octet string prefixed with an encoded length. The encoding C<$format>
		1103	uses the same format as a Perl C<pack> format, but must specify a single
		1104	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1105	optional C<!>, C<< < >> or C<< > >> modifier).
		1106
		1107	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1108	EPP uses a prefix of C<N> (4 octtes).
		1109
		1110	Example: read a block of data prefixed by its length in BER-encoded
		1111	format (very efficient).
		1112
		1113	$handle->push_read (packstring => "w", sub {
		1114	my ($handle, $data) = @_;
		1115	});
		1116
		1117	=cut
		1118
		1119	register_read_type packstring => sub {
		1120	my ($self, $cb, $format) = @_;
		1121
		1122	sub {
		1123	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1124	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1125	or return;
		1126
		1127	$format = length pack $format, $len;
		1128
		1129	# bypass unshift if we already have the remaining chunk
		1130	if ($format + $len <= length $_[0]{rbuf}) {
		1131	my $data = substr $_[0]{rbuf}, $format, $len;
		1132	substr $_[0]{rbuf}, 0, $format + $len, "";
		1133	$cb->($_[0], $data);
		1134	} else {
		1135	# remove prefix
		1136	substr $_[0]{rbuf}, 0, $format, "";
		1137
		1138	# read remaining chunk
		1139	$_[0]->unshift_read (chunk => $len, $cb);
		1140	}
		1141
		1142	1
		1143	}
		1144	};
		1145
		1146	=item json => $cb->($handle, $hash_or_arrayref)
		1147
		1148	Reads a JSON object or array, decodes it and passes it to the callback.
		1149
		1150	If a C<json> object was passed to the constructor, then that will be used
		1151	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1152
		1153	This read type uses the incremental parser available with JSON version
		1154	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1155	dependency on your own: this module will load the JSON module, but
		1156	AnyEvent does not depend on it itself.
		1157
		1158	Since JSON texts are fully self-delimiting, the C<json> read and write
		1159	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1160	the C<json> write type description, above, for an actual example.
		1161
		1162	=cut
		1163
		1164	register_read_type json => sub {
		1165	my ($self, $cb) = @_;
		1166
		1167	require JSON;
		1168
		1169	my $data;
		1170	my $rbuf = \$self->{rbuf};
		1171
		1172	my $json = $self->{json} ||= JSON->new->utf8;
		1173
		1174	sub {
		1175	my $ref = $json->incr_parse ($self->{rbuf});
		1176
		1177	if ($ref) {
		1178	$self->{rbuf} = $json->incr_text;
		1179	$json->incr_text = "";
		1180	$cb->($self, $ref);
		1181
		1182	1
		1183	} else {
		1184	$self->{rbuf} = "";
		1185	()
		1186	}
		1187	}
		1188	};
		1189
		1190	=item storable => $cb->($handle, $ref)
		1191
		1192	Deserialises a L<Storable> frozen representation as written by the
		1193	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1194	data).
		1195
		1196	Raises C<EBADMSG> error if the data could not be decoded.
		1197
		1198	=cut
		1199
		1200	register_read_type storable => sub {
		1201	my ($self, $cb) = @_;
		1202
		1203	require Storable;
		1204
		1205	sub {
		1206	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1207	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1208	or return;
		1209
		1210	my $format = length pack "w", $len;
		1211
		1212	# bypass unshift if we already have the remaining chunk
		1213	if ($format + $len <= length $_[0]{rbuf}) {
		1214	my $data = substr $_[0]{rbuf}, $format, $len;
		1215	substr $_[0]{rbuf}, 0, $format + $len, "";
		1216	$cb->($_[0], Storable::thaw ($data));
		1217	} else {
		1218	# remove prefix
		1219	substr $_[0]{rbuf}, 0, $format, "";
		1220
		1221	# read remaining chunk
		1222	$_[0]->unshift_read (chunk => $len, sub {
		1223	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1224	$cb->($_[0], $ref);
		1225	} else {
		1226	$self->_error (&Errno::EBADMSG);
		1227	}
		1228	});
		1229	}
		1230
		1231	1
		1232	}
		1233	};
		1234
		1235	=back
		1236
		1237	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
		1238
		1239	This function (not method) lets you add your own types to C<push_read>.
		1240
		1241	Whenever the given C<type> is used, C<push_read> will invoke the code
		1242	reference with the handle object, the callback and the remaining
		1243	arguments.
		1244
		1245	The code reference is supposed to return a callback (usually a closure)
		1246	that works as a plain read callback (see C<< ->push_read ($cb) >>).
		1247
		1248	It should invoke the passed callback when it is done reading (remember to
		1249	pass C<$handle> as first argument as all other callbacks do that).
		1250
		1251	Note that this is a function, and all types registered this way will be
		1252	global, so try to use unique names.
		1253
		1254	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,
		1255	search for C<register_read_type>)).
		1256
		1257	=item $handle->stop_read
		1258
		1259	=item $handle->start_read
		1260
		1261	In rare cases you actually do not want to read anything from the
		1262	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
		1263	any queued callbacks will be executed then. To start reading again, call
		1264	C<start_read>.
		1265
		1266	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1267	you change the C<on_read> callback or push/unshift a read callback, and it
		1268	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1269	there are any read requests in the queue.
		1270
		1271	These methods will have no effect when in TLS mode (as TLS doesn't support
		1272	half-duplex connections).
		1273
		1274	=cut
		1275
		1276	sub stop_read {
		1277	my ($self) = @_;
		1278
		1279	delete $self->{_rw} unless $self->{tls};
		1280	}
		1281
		1282	sub start_read {
		1283	my ($self) = @_;
		1284
		1285	unless ($self->{_rw} || $self->{_eof}) {
		1286	Scalar::Util::weaken $self;
		1287
		1288	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
		1289	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
		1290	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
		1291
		1292	if ($len > 0) {
		1293	$self->{_activity} = AnyEvent->now;
		1294
		1295	if ($self->{tls}) {
		1296	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1297
		1298	&_dotls ($self);
		1299	} else {
		1300	$self->_drain_rbuf unless $self->{_in_drain};
		1301	}
		1302
		1303	} elsif (defined $len) {
		1304	delete $self->{_rw};
		1305	$self->{_eof} = 1;
		1306	$self->_drain_rbuf unless $self->{_in_drain};
		1307
		1308	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		1309	return $self->_error ($!, 1);
184	}	1310	}
185	});	1311	});
		1312	}
186	}	1313	}
187		1314
188	=item B<on_error ($callback)>	1315	# poll the write BIO and send the data if applicable
189		1316	sub _dotls {
190	Whenever a read or write operation resulted in an error the C<$callback>
191	will be called.
192
193	The first argument of C<$callback> will be the L<AnyEvent::Handle> object itself.
194	The error is given as errno in C<$!>.
195
196	=cut
197
198	sub on_error {
199	$_[0]->{on_error} = $_[1];
200	}
201
202	=item B<on_eof ($callback)>
203
204	Installs the C<$callback> that will be called when the end of file is
205	encountered in a read operation this C<$callback> will be called. The first
206	argument will be the L<AnyEvent::Handle> object itself.
207
208	=cut
209
210	sub on_eof {
211	$_[0]->{on_eof} = $_[1];
212	}
213
214	=item B<rbuf>
215
216	Returns a reference to the read buffer.
217
218	NOTE: The read buffer should only be used or modified if the C<on_read>
219	method is used directly. The C<read> and C<readlines> methods will provide
220	the read data to their callbacks.
221
222	=cut
223
224	sub rbuf : lvalue {
225	$_[0]->{rbuf}
226	}
227
228	=item B<read ($len, $callback)>
229
230	Will read exactly C<$len> bytes from the filehandle and call the C<$callback>
231	if done so. The first argument to the C<$callback> will be the L<AnyEvent::Handle>
232	object itself and the second argument the read data.
233
234	NOTE: This method will override any callbacks installed via the C<on_read> method.
235
236	=cut
237
238	sub read {
239	my ($self, $len, $cb) = @_;	1317	my ($self) = @_;
240		1318
241	$self->{read_cb} = $cb;	1319	my $tmp;
242	my $old_blk_size = $self->{read_block_size};
243	$self->{read_block_size} = $len;
244		1320
245	$self->on_read (sub {	1321	if (length $self->{_tls_wbuf}) {
246	#d# warn "OFOFO $len || ".length($_[0]->{rbuf})."||\n";	1322	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
247		1323	substr $self->{_tls_wbuf}, 0, $tmp, "";
248	if ($len == length $_[0]->{rbuf}) {
249	$_[0]->{read_block_size} = $old_blk_size;
250	$_[0]->on_read (undef);
251	$_[0]->{read_cb}->($_[0], (substr $self->{rbuf}, 0, $len, ''));
252	}	1324	}
253	});	1325	}
254	}
255		1326
256	=item B<readlines ($callback)>	1327	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1328	unless (length $tmp) {
		1329	# let's treat SSL-eof as we treat normal EOF
		1330	delete $self->{_rw};
		1331	$self->{_eof} = 1;
		1332	&_freetls;
		1333	}
257		1334
258	=item B<readlines ($sep, $callback)>	1335	$self->{rbuf} .= $tmp;
		1336	$self->_drain_rbuf unless $self->{_in_drain};
		1337	$self->{tls} or return; # tls session might have gone away in callback
		1338	}
259		1339
260	This method will read lines from the filehandle, seperated by C<$sep> or C<"\n">	1340	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
261	if C<$sep> is not provided. C<$sep> will be used as part of a regex, so it can be
262	a regex itself and won't be quoted!
263		1341
264	The C<$callback> will be called when at least one	1342	if ($tmp != Net::SSLeay::ERROR_WANT_READ ()) {
265	line could be read. The first argument to the C<$callback> will be the L<AnyEvent::Handle>	1343	if ($tmp == Net::SSLeay::ERROR_SYSCALL ()) {
266	object itself and the rest of the arguments will be the read lines.	1344	return $self->_error ($!, 1);
		1345	} elsif ($tmp == Net::SSLeay::ERROR_SSL ()) {
		1346	return $self->_error (&Errno::EIO, 1);
		1347	}
267		1348
268	NOTE: This method will override any callbacks installed via the C<on_read> method.	1349	# all other errors are fine for our purposes
		1350	}
269		1351
270	=cut	1352	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
		1353	$self->{wbuf} .= $tmp;
		1354	$self->_drain_wbuf;
		1355	}
		1356	}
271		1357
272	sub readlines {	1358	=item $handle->starttls ($tls[, $tls_ctx])
		1359
		1360	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1361	object is created, you can also do that at a later time by calling
		1362	C<starttls>.
		1363
		1364	The first argument is the same as the C<tls> constructor argument (either
		1365	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1366
		1367	The second argument is the optional C<Net::SSLeay::CTX> object that is
		1368	used when AnyEvent::Handle has to create its own TLS connection object.
		1369
		1370	The TLS connection object will end up in C<< $handle->{tls} >> after this
		1371	call and can be used or changed to your liking. Note that the handshake
		1372	might have already started when this function returns.
		1373
		1374	If it an error to start a TLS handshake more than once per
		1375	AnyEvent::Handle object (this is due to bugs in OpenSSL).
		1376
		1377	=cut
		1378
		1379	sub starttls {
273	my ($self, $NL, $cb) = @_;	1380	my ($self, $ssl, $ctx) = @_;
274		1381
275	if (ref $NL) {	1382	require Net::SSLeay;
276	$cb = $NL;	1383
277	$NL = "\n";	1384	Carp::croak "it is an error to call starttls more than once on an Anyevent::Handle object"
		1385	if $self->{tls};
278	}	1386
279		1387	if ($ssl eq "accept") {
280	$self->{on_readline} = $cb;	1388	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
281		1389	Net::SSLeay::set_accept_state ($ssl);
282	$self->on_read (sub {	1390	} elsif ($ssl eq "connect") {
283	my @lines;	1391	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
284	push @lines, $1 while $_[0]->{rbuf} =~ s/(.*)$NL//;	1392	Net::SSLeay::set_connect_state ($ssl);
285	$self->{on_readline}->($_[0], @lines);
286	});	1393	}
287	}
288		1394
289	=item B<write ($data)>	1395	$self->{tls} = $ssl;
290		1396
291	=item B<write ($callback)>	1397	# basically, this is deep magic (because SSL_read should have the same issues)
		1398	# but the openssl maintainers basically said: "trust us, it just works".
		1399	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		1400	# and mismaintained ssleay-module doesn't even offer them).
		1401	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1402	#
		1403	# in short: this is a mess.
		1404	#
		1405	# note that we do not try to keep the length constant between writes as we are required to do.
		1406	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1407	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1408	# have identity issues in that area.
		1409	Net::SSLeay::CTX_set_mode ($self->{tls},
		1410	(eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		1411	| (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
292		1412
293	=item B<write ($data, $callback)>	1413	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		1414	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
294		1415
295	This method will write C<$data> to the filehandle and call the C<$callback>	1416	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
296	afterwards. If only C<$callback> is provided it will be called when the
297	write buffer becomes empty the next time (or immediately if it already is empty).
298		1417
299	=cut	1418	&_dotls; # need to trigger the initial handshake
300		1419	$self->start_read; # make sure we actually do read
301	sub write {
302	my ($self, $data, $cb) = @_;
303	if (ref $data) { $cb = $data; undef $data }
304	push @{$self->{write_bufs}}, [$data, $cb];
305	$self->_check_writer;
306	}	1420	}
307		1421
308	sub _check_writer {	1422	=item $handle->stoptls
		1423
		1424	Shuts down the SSL connection - this makes a proper EOF handshake by
		1425	sending a close notify to the other side, but since OpenSSL doesn't
		1426	support non-blocking shut downs, it is not possible to re-use the stream
		1427	afterwards.
		1428
		1429	=cut
		1430
		1431	sub stoptls {
309	my ($self) = @_;	1432	my ($self) = @_;
310		1433
311	if ($self->{write_w}) {	1434	if ($self->{tls}) {
312	unless ($self->{write_cb}) {	1435	Net::SSLeay::shutdown ($self->{tls});
313	while (@{$self->{write_bufs}} && not defined $self->{write_bufs}->[0]->[1]) {	1436
314	my $wba = shift @{$self->{write_bufs}};	1437	&_dotls;
315	$self->{wbuf} .= $wba->[0];	1438
316	}	1439	# we don't give a shit. no, we do, but we can't. no...
317	}	1440	# we, we... have to use openssl :/
318	return;	1441	&_freetls;
		1442	}
		1443	}
		1444
		1445	sub _freetls {
		1446	my ($self) = @_;
		1447
		1448	return unless $self->{tls};
		1449
		1450	Net::SSLeay::free (delete $self->{tls});
319	}	1451
		1452	delete @$self{qw(_rbio _wbio _tls_wbuf)};
		1453	}
320		1454
321	my $wba = shift @{$self->{write_bufs}}	1455	sub DESTROY {
322	or return;	1456	my $self = shift;
323		1457
324	unless (defined $wba->[0]) {	1458	&_freetls;
325	$wba->[1]->($self) if $wba->[1];
326	$self->_check_writer;
327	return;
328	}
329		1459
330	$self->{wbuf} = $wba->[0];	1460	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
331	$self->{write_cb} = $wba->[1];
332		1461
333	$self->{write_w} =	1462	if ($linger && length $self->{wbuf}) {
334	AnyEvent->io (poll => 'w', fh => $self->{fh}, cb => sub {	1463	my $fh = delete $self->{fh};
		1464	my $wbuf = delete $self->{wbuf};
		1465
		1466	my @linger;
		1467
		1468	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
335	my $l = syswrite $self->{fh}, $self->{wbuf}, length $self->{wbuf};	1469	my $len = syswrite $fh, $wbuf, length $wbuf;
336		1470
337	if (not defined $l) {	1471	if ($len > 0) {
338	return if $! == EAGAIN || $! == EINTR;	1472	substr $wbuf, 0, $len, "";
339	delete $self->{write_w};
340	$self->{on_error}->($self) if $self->{on_error};
341
342	} else {	1473	} else {
343	substr $self->{wbuf}, 0, $l, '';	1474	@linger = (); # end
344
345	if (length ($self->{wbuf}) == 0) {
346	$self->{write_cb}->($self) if $self->{write_cb};
347
348	delete $self->{write_w};
349	delete $self->{wbuf};
350	delete $self->{write_cb};
351
352	$self->_check_writer;
353	}
354	}	1475	}
355	});	1476	});
		1477	push @linger, AnyEvent->timer (after => $linger, cb => sub {
		1478	@linger = ();
		1479	});
		1480	}
		1481	}
		1482
		1483	=item AnyEvent::Handle::TLS_CTX
		1484
		1485	This function creates and returns the Net::SSLeay::CTX object used by
		1486	default for TLS mode.
		1487
		1488	The context is created like this:
		1489
		1490	Net::SSLeay::load_error_strings;
		1491	Net::SSLeay::SSLeay_add_ssl_algorithms;
		1492	Net::SSLeay::randomize;
		1493
		1494	my $CTX = Net::SSLeay::CTX_new;
		1495
		1496	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
		1497
		1498	=cut
		1499
		1500	our $TLS_CTX;
		1501
		1502	sub TLS_CTX() {
		1503	$TLS_CTX || do {
		1504	require Net::SSLeay;
		1505
		1506	Net::SSLeay::load_error_strings ();
		1507	Net::SSLeay::SSLeay_add_ssl_algorithms ();
		1508	Net::SSLeay::randomize ();
		1509
		1510	$TLS_CTX = Net::SSLeay::CTX_new ();
		1511
		1512	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
		1513
		1514	$TLS_CTX
		1515	}
356	}	1516	}
357		1517
358	=back	1518	=back
359		1519
		1520
		1521	=head1 NONFREQUENTLY ASKED QUESTIONS
		1522
		1523	=over 4
		1524
		1525	=item How do I read data until the other side closes the connection?
		1526
		1527	If you just want to read your data into a perl scalar, the easiest way
		1528	to achieve this is by setting an C<on_read> callback that does nothing,
		1529	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1530	will be in C<$_[0]{rbuf}>:
		1531
		1532	$handle->on_read (sub { });
		1533	$handle->on_eof (undef);
		1534	$handle->on_error (sub {
		1535	my $data = delete $_[0]{rbuf};
		1536	undef $handle;
		1537	});
		1538
		1539	The reason to use C<on_error> is that TCP connections, due to latencies
		1540	and packets loss, might get closed quite violently with an error, when in
		1541	fact, all data has been received.
		1542
		1543	It is usually better to use acknowledgements when transfering data,
		1544	to make sure the other side hasn't just died and you got the data
		1545	intact. This is also one reason why so many internet protocols have an
		1546	explicit QUIT command.
		1547
		1548
		1549	=item I don't want to destroy the handle too early - how do I wait until
		1550	all data has been written?
		1551
		1552	After writing your last bits of data, set the C<on_drain> callback
		1553	and destroy the handle in there - with the default setting of
		1554	C<low_water_mark> this will be called precisely when all data has been
		1555	written to the socket:
		1556
		1557	$handle->push_write (...);
		1558	$handle->on_drain (sub {
		1559	warn "all data submitted to the kernel\n";
		1560	undef $handle;
		1561	});
		1562
		1563	=back
		1564
		1565
		1566	=head1 SUBCLASSING AnyEvent::Handle
		1567
		1568	In many cases, you might want to subclass AnyEvent::Handle.
		1569
		1570	To make this easier, a given version of AnyEvent::Handle uses these
		1571	conventions:
		1572
		1573	=over 4
		1574
		1575	=item * all constructor arguments become object members.
		1576
		1577	At least initially, when you pass a C<tls>-argument to the constructor it
		1578	will end up in C<< $handle->{tls} >>. Those members might be changed or
		1579	mutated later on (for example C<tls> will hold the TLS connection object).
		1580
		1581	=item * other object member names are prefixed with an C<_>.
		1582
		1583	All object members not explicitly documented (internal use) are prefixed
		1584	with an underscore character, so the remaining non-C<_>-namespace is free
		1585	for use for subclasses.
		1586
		1587	=item * all members not documented here and not prefixed with an underscore
		1588	are free to use in subclasses.
		1589
		1590	Of course, new versions of AnyEvent::Handle may introduce more "public"
		1591	member variables, but thats just life, at least it is documented.
		1592
		1593	=back
		1594
360	=head1 AUTHOR	1595	=head1 AUTHOR
361		1596
362	Robin Redeker, C<< <elmex at ta-sa.org> >>	1597	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
363		1598
364	=cut	1599	=cut
365		1600
366	1; # End of AnyEvent::Handle	1601	1; # End of AnyEvent::Handle

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